class Rust < Formula
  desc "Safe, concurrent, practical language"
  homepage "https://www.rust-lang.org/"

  stable do
    url "https://static.rust-lang.org/dist/rustc-1.22.1-src.tar.gz"
    sha256 "8b7a42bdd6eb205a8c533eb41b5c42389a88158d060aed1e0f461f68c1fd3fd3"

    resource "cargo" do
      url "https://github.com/rust-lang/cargo.git",
          :tag => "0.22.0",
          :revision => "3423351a5d75ac7377bb15987842aadcfd068ad2"
    end

    resource "racer" do
      url "https://github.com/racer-rust/racer/archive/2.0.12.tar.gz"
      sha256 "1fa063d90030c200d74efb25b8501bb9a5add7c2e25cbd4976adf7a73bf715cc"
    end
  end

  bottle do
    sha256 "f20bd883470995e102ce4a76a074d10f53b17a9359c9065b1781ce37da6faaf3" => :high_sierra
    sha256 "e281337dfd6a0291f231e4efc9fe72e3fc8a070b7e41c69944ddfc4371d350dc" => :sierra
    sha256 "5791955f53485bbe4ec6b2ffa7ce837e63630996ccebb775962a245911bdc6ee" => :el_capitan
  end

  head do
    url "https://github.com/rust-lang/rust.git"

    resource "cargo" do
      url "https://github.com/rust-lang/cargo.git"
    end
  end

  option "with-llvm", "Build with brewed LLVM. By default, Rust's LLVM will be used."
  option "with-racer", "Build Racer code completion tool, and retain Rust sources."

  depends_on "cmake" => :build
  depends_on "pkg-config" => :run
  depends_on "llvm" => :optional
  depends_on "openssl"
  depends_on "libssh2"

  conflicts_with "cargo-completion", :because => "both install shell completion for cargo"

  # According to the official readme, GCC 4.7+ is required
  fails_with :gcc_4_0
  fails_with :gcc
  ("4.3".."4.6").each do |n|
    fails_with :gcc => n
  end

  resource "cargobootstrap" do
    # From https://github.com/rust-lang/rust/blob/#{version}/src/stage0.txt
    url "https://static.rust-lang.org/dist/2017-10-12/cargo-0.22.0-x86_64-apple-darwin.tar.gz"
    sha256 "8968697ae6eef3b178438a6d5563f531e499308dcea7f4915665dbcec54c851a"
  end

  def install
    # Fix build failure for compiler_builtins "error: invalid deployment target
    # for -stdlib=libc++ (requires OS X 10.7 or later)"
    ENV["MACOSX_DEPLOYMENT_TARGET"] = MacOS.version

    # Fix build failure for cmake v0.1.24 "error: internal compiler error:
    # src/librustc/ty/subst.rs:127: impossible case reached" on 10.11, and for
    # libgit2-sys-0.6.12 "fatal error: 'os/availability.h' file not found
    # #include <os/availability.h>" on 10.11 and "SecTrust.h:170:67: error:
    # expected ';' after top level declarator" among other errors on 10.12
    ENV["SDKROOT"] = MacOS.sdk_path

    args = ["--prefix=#{prefix}"]
    args << "--disable-rpath" if build.head?
    args << "--llvm-root=#{Formula["llvm"].opt_prefix}" if build.with? "llvm"
    if build.head?
      args << "--release-channel=nightly"
    else
      args << "--release-channel=stable"
    end
    system "./configure", *args
    system "make"
    system "make", "install"

    resource("cargobootstrap").stage do
      system "./install.sh", "--prefix=#{buildpath}/cargobootstrap"
    end
    ENV.prepend_path "PATH", buildpath/"cargobootstrap/bin"

    resource("cargo").stage do
      ENV["RUSTC"] = bin/"rustc"
      system "cargo", "build", "--release", "--verbose"
      bin.install "target/release/cargo"
    end

    if build.with? "racer"
      resource("racer").stage do
        ENV.prepend_path "PATH", bin
        cargo_home = buildpath/"cargo_home"
        cargo_home.mkpath
        ENV["CARGO_HOME"] = cargo_home
        system bin/"cargo", "build", "--release", "--verbose"
        (libexec/"bin").install "target/release/racer"
        (bin/"racer").write_env_script(libexec/"bin/racer", :RUST_SRC_PATH => pkgshare/"rust_src")
      end
      # Remove any binary files; as Homebrew will run ranlib on them and barf.
      rm_rf Dir["src/{llvm,test,librustdoc,etc/snapshot.pyc}"]
      (pkgshare/"rust_src").install Dir["src/*"]
    end

    rm_rf prefix/"lib/rustlib/uninstall.sh"
    rm_rf prefix/"lib/rustlib/install.log"
  end

  def post_install
    Dir["#{lib}/rustlib/**/*.dylib"].each do |dylib|
      chmod 0664, dylib
      MachO::Tools.change_dylib_id(dylib, "@rpath/#{File.basename(dylib)}")
      chmod 0444, dylib
    end
  end

  test do
    system "#{bin}/rustdoc", "-h"
    (testpath/"hello.rs").write <<~EOS
      fn main() {
        println!("Hello World!");
      }
    EOS
    system "#{bin}/rustc", "hello.rs"
    assert_equal "Hello World!\n", `./hello`
    system "#{bin}/cargo", "new", "hello_world", "--bin"
    assert_equal "Hello, world!",
                 (testpath/"hello_world").cd { `#{bin}/cargo run`.split("\n").last }
  end
end